#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
int main()
{
	int n = 0; 
	int m = 0;
	int k = 0;
	scanf("%d %d %d", &n, &m, &k);
	int arr[301][301] = { 0 };
	int p = 0;
	int q = 0;
	for (int i = 0; i < k; i++)
	{
		scanf("%d %d", &p,&q);
		arr[p][q] = 1;
	}
	int ans = 0;
	int flag = 0;
	for(int j = 0;j<k;j++)
	{
		if (arr[p - 1][q] != 1 && arr[p][q - 1] != 1 && arr[p + 1][q]!=1 && arr[p][q + 1]!=1)
		{
			ans += 4;
		}
		if (arr[p - 1][q] == 1 || arr[p][q - 1] == 1 || arr[p + 1][q] == 1 || arr[p][q + 1] == 1)
		{
			flag++;
			ans += 3;
		}
		if ((arr[p - 1][q] == 1 && arr[p][q - 1] == 1 )|| 
			(arr[p - 1][q] == 1 && arr[p + 1][q] == 1 )||
			(arr[p - 1][q] == 1 && arr[p][q + 1] == 1 )||
			(arr[p + 1][q] == 1 && arr[p][q - 1] == 1 )||
			(arr[p + 1][q] == 1 && arr[p][q + 1] == 1 )||
			(arr[p][q - 1] == 1 && arr[p][q + 1] == 1 ) )
		{
			ans+=2;
		}
		if ((arr[p - 1][q] == 1 && arr[p][q - 1] == 1 && arr[p + 1][q] == 1)||
			(arr[p][q - 1] == 1 && arr[p - 1][q] == 1 && arr[p][q + 1] == 1)||
			(arr[p - 1][q] == 1 && arr[p][q + 1] == 1 && arr[p + 1][q] == 1)||
			(arr[p][q + 1] == 1 && arr[p - 1][q] == 1 && arr[p][q + 1] == 1) )
		{
			ans+=1;
		}
	}
	if (flag !=0)
	{
		ans += flag/2;
	}
	printf("%d", ans);
	return 0;
}



int main()
{
	int n = 0;
	int m = 0;
	int k = 0;
	scanf("%d %d %d", &n, &m, &k);
	int arr[301][301] = { 0 };
	int p = 0;
	int q = 0;
	int ans = 4 * k;
	int flag1 = 0;
	int flag2 = 0;
	int flag3 = 0;
	for (int i = 0; i < k; i++)
	{
		scanf("%d %d", &p, &q);
		arr[p][q] = 1;

		
		if (arr[p - 1][q] == 1 || arr[p][q - 1] == 1 || arr[p + 1][q] == 1 || arr[p][q + 1] == 1)
		{
			flag1++;
		}
		if ((arr[p - 1][q] == 1 && arr[p][q - 1] == 1) ||
			(arr[p - 1][q] == 1 && arr[p + 1][q] == 1) ||
			(arr[p - 1][q] == 1 && arr[p][q + 1] == 1) ||
			(arr[p + 1][q] == 1 && arr[p][q - 1] == 1) ||
			(arr[p + 1][q] == 1 && arr[p][q + 1] == 1) ||
			(arr[p][q - 1] == 1 && arr[p][q + 1] == 1))
		{
			flag2++;
		}
		if ((arr[p - 1][q] == 1 && arr[p][q - 1] == 1 && arr[p + 1][q] == 1) ||
			(arr[p][q - 1] == 1 && arr[p - 1][q] == 1 && arr[p][q + 1] == 1) ||
			(arr[p - 1][q] == 1 && arr[p][q + 1] == 1 && arr[p + 1][q] == 1) ||
			(arr[p][q + 1] == 1 && arr[p - 1][q] == 1 && arr[p][q + 1] == 1))
		{
			flag3++;
		}
	}
	ans = ans - flag1 / 2 - 2 * flag2 - 3 * flag3 / 3;
	printf("%d", ans);
	return 0;
}




int main()
{
	int n = 0;
	int m = 0;
	int k = 0;
	int p = 0; 
	int q = 0;
	int arr[301][301] = { 0 };
	scanf("%d %d %d", &n, &m, &k);
	for (int i = 0; i < k; i++)
	{
		scanf("%d %d", &p,&q);

	}





	return 0;
}